A wireless sensor network includes nodes and base stations. Nodes are the deployed wireless sensors for perceiving events or monitoring environment, and sending the perceived or monitored data to base stations via the multi-hop wireless transmission; and base stations are established for collecting, storing, and processing the perceived or monitored data. However, there are some problems: one aspect is that the wireless sensor network is attacked more easily (e.g. wiretapped, disturbed, and injected by erroneous data) due to the characteristics of wireless communication, also the privacy leakage from the source (i.e. the monitored object), base stations and the perceived or monitored data may exist in the wireless communication; the other aspect is that the prior security technology can not be applied directly into the wireless sensor network due to disadvantages of the deployed wireless sensors (e.g. small size; limited computing power, storage capacity, and RF communication range; using batteries) and complexity of the wireless sensor network.
Particularly, in some applications of the wireless sensor network, once the location information of the source is leaked, serious safety problems will be caused. For example, when monitoring the endangered animals' habits for scientific research or the real-time battlefield environment by the wireless sensor network, it is important to protect the source in the wireless sensor network. In these applications, once the location information of the source is leaked, it can be used by the attacker (such as hunters or enemies), which makes the source (such as endangered animals or soldiers) easily leaked, thus resulting significant losses.
FIG. 1 is a schematic diagram of the source being traced by the attacker according to a conventional technology. As shown in FIG. 1, the monitored data corresponding to the source is obtained by point 1 which has a shortest distance from the source, and then the monitored data is sent via the wireless link to the base station. As shown in (a) in FIG. 1, the attacker is waiting at the base station to wiretap the monitored data. When the monitored data is wiretapped, the attacker can determine the sending node is point 6 by the radio positioning technology. As shown in (b) in FIG. 1, the attacker can move to point 6 to wiretap the monitored data continually. As shown in (c) in FIG. 1, the attacker can move to point 1 to find the source. Therefore, it can be seen that the source (such as endangered animals or soldiers) is traced more easily by the attacker by the simple routing, in other words, there is no security protection for the source by using the shortest path routing.